Improved coffer-dam



UNITED STATES PATENT OrrIcEo JAMES BRAIDWOOD, 0F WILMINGTON, ILLINOIS.

IMPROVED COFFER-DAIVI.

Specification forming part of Letters Patent No. 55,235, dated June 5, 1866.

To all whom 'it 'may concern:

Be it known that I, JAMES BRAIDWOOD, ot' Wilmington, in the county of Will and State of Illinois, have invented a certain new and useful Improvement in Cotter-Dams; and I do hereby declare that the following is afull, clear, and exact description thereof, reference being had to the accompanying dra-wings, and to the letters and marks thereon.

Of the drawings forming part of this specification, Figure l is a view of a coi'i'erdam having my improvement forming a part thereof, the view being what is usually termed a top View, or a View had by looking' down 4on the structure7 and showing the interior thereof, while Fig. 2 is a view by vertical section.

In both ot' these iigures, wherelike parts are shown, like marks and letters are used to indicate the parts. I

The drawings represent the coffer-dam as being' of rectangular form; but, as is evident, it may be cylindrical, or of any other form that may be regarded as the most suitable for the particular work to be done, and the several parts of the structure may be ot' iron or of some o ther metal, or of wood, or some parts of metal and other parts ot' wood, as may be deemed number' of the sections being' greater or less,

as may be required. The upper section may be in part of metal and part of timber, c, and the continuing' sections entirelyI ot timber, securely connected, as is indicated by the section b.

At the point of union ot' the sections, as at d, I surround the joint with an elastic valve, e, which by the material without, will be pressed against the joint under suiicient force to keep out water, quicksand, &c. This valve may be nailed or otherwise attached to the surfaces of the timbers about it to keep it in place.

The upper surface oftheinner section (marked f) will afford a bearing for the screw g, or such other mechanical devices as may be used to force the section downward, which screw may have Yt'or its guide a plate, h, aftlxed to a rod or bar, i, with the female screw in the plate, and the turned ends of the rod or bar z' may be titted into sockets j. securely connected to the upper section, so that when the upper section is rmly held,either by its own weightor by 11'Xtures,the application of power by the screw or other means will force the lower section down.

Each additional section can therefore be provided with the means for forcing the section below, or to be below it, down, the invention permitting ot quite a number of sections and of the separating and dei aching ofthe one secltion from the other, thus rendering the cofferdam portable and ot easy carriage and trans-v portation. t

As is evident, in some instances hydraulic pressure may be used for forcing down the sections.

Bracin gs or ties lc, with their ends fitting into sockets, as shown at Z, and easily detached, may be used in such number and at such points as may be needed to strengthen and support the sides ot' the upper or other sections.

What I claim as new in the construction of coiffer-dams, and desire to secure by Letters Patent, is-

1. The making them of sections that may be litted within each other, and operated and detached from each other, substantially as herein recited. f

2. The elastic valve surrounding the points of union of the sections and made tight by the outward pressure, as described.

3. The detachable mechanical means or devices for forcing down the sections by pressure upon the surfaces, as set forth.

This specification signed this 15th day of March, 1866.

JAMES EEArDwooD.

Witnesses z JAMES L. YOUNG, A. WHITTEN. 

